ch 3 ecosystems: what they are and how do they work?

Ch 3Ecosystems: What They Are and

How Do They Work?

Case StudyHave You Thanked The Insects Today?

(Summarize)

The Nature of EcologyEcology: the study of how organisms

interact with one another and their environment.

Organism:Species:Population:Community:Ecosystem:Biosphere:

The Earth’s Life-Support SystemsFour Spheres (that make up the biosphere)

Atmosphere:Troposphere:

Contains majority of planet’s air (nitrogen, oxygen)

Stratosphere:Contains the ozone layer

Hydrosphere:

Lithosphere:

The Earth’s Life-Support SystemsSolar energy, the cycling of matter, and

gravity sustain the earth’s life.Solar energy warms the planet, runs the

water cycle (80%), generates winds (1%) and supports plant growth through photosynthesis (0.1%).

Natural Greenhouse effect:

Ecosystem ComponentsBiomes:

Ex: Forests, deserts, grasslands

Aquatic Life Zones:Ex: Lakes, Oceans, Rivers

Biotic:Ex: producers (plants), consumers (animals)

Abiotic:Ex: wind, temperature, water, air

Ecosystem ComponentsAvailability of matter and energy resources

can limit the number of organisms in a population.

Limiting factor (principle):

Ex: precipitation can be a limiting factor.

Ecosystem Components Producers (autotrophs):

Photosynthesis: (Write equation):

Consumers (heterotrophs):

Primary consumers( herbivores):

Secondary consumers (carnivores):

Third and higher level consumers:

Omnivores:

Decomposers:

BiodiversityBiodiversity:

Human activities are destroying and degrading the habitats for many wild species and driving some of them to premature extinction.HIPPO:

H-I-P-P-O-

Energy Flow In EcosystemsFood chains:

Trophic levels:

Food webs:

Ecological Efficiency:

10% rule: typically 10% energy moves from one trophic level to the next (losing 90% at each level to survival).

Soil: Renewable ResourceSoil:

Soil formation starts when bedrock is broken down into small pieces by weathering. Lichen add nutrients. Over hundreds of years inorganic and organic matter builds up on the bedrock .

Renewed very slow. Can take 15 yrs to form 1 cm of soil.

Humans have accelerated soil erosion causing it to become a nonrenewable resource.

Matter Cycling in EcosystemsNutrients:

Biogeochemical cycles (nutrient cycles):

Hydrologic cycle (water cycle):

Powered by the sunOnly 0.024% of all the water on earth is

available freshwater.

Human Effects on Water Cycle4 ways

We use it quicker then it can replenish itself.We clear vegetation to build infrastructure

which decreases infiltration that recharges groundwater. Can also cause flooding and accelerate erosion.

We add nutrients (phosphate and nitrate) to water which can cause algae blooms.

Water cycle is speeding up due to man made climate change.

Carbon CycleCarbon Cycle:

Human effectsClearing of trees and other plants that absorb

CO2We add CO2 to the atmosphere by burning

fossil fuels and wood.

Nitrogen cycleNitrogen Cycle:

Human effectsWe add NO to atmosphere which can cause acid

rain.We add N2O through livestock and fertilizer

which can cause ozone depletion.NO3 can leach into groundwaterRelease NO stored in trees when we clear forests.Remove N from top soil when we irrigate crops.